Using multiple sources

Hello.. I'm using media stream on a windows PC and was wondering how or if I can use multiple sources to provide my videos.

I have a hard drive on my windows pc that is running xbmc and everything is working great! Fanart, episodes, etc..

I have an external hard drive that is networked to my xbmc pc and I've added the external hard drive as a new source. Is there a way to scan this new external hard drive so the videos on this hard drive show up in my library?

gabbott - thanks for the reply. I'm getting the videos to show up in the library, but I'm having to scan them each individually. XBMC scans my other hard drive for new videos upon start up and adds them. Can I have this happen with the external hard drive?